(1) Field of the Invention
The present invention relates generally to systems and methods for testing multi-conductor cables and, more particularly, to a wireless multiconductor cable tester and method.
(2) Description of the Prior Art
Multiconductor cable is required for many electronic devices such as digital equipment to provide a plurality of signal paths for digital signals. A typical multiconductor cable may be comprised of many conductors to permit simultaneous parallel transmission of multiple digital signals, control signals, DC power levels, and the like. For instance, one typical multiconductor cable has a standard one hundred conductor construction with suitable connectors on either end. Depending on the type of installation, multiconductor cables may extend distances several hundred feet long. Many types of problems may arise with such cables including but not limited to, miswirings such as miswiring of appropriate pins on the plugs of opposite ends of the cable, open circuits or lack of continuity, shorts, and the like. In some cases, the multiconductor cable may be provided in standard sections, such as twenty-five foot sections, so that suitable lengths require connecting several different sections of the cable together.
During fabrication, closed loop testing of the multiconductor cable is facilitated because both ends of the uninstalled multiconductor cable are readily available for connection to a closed loop multiconductor cable tester. In this situation, it is possible to easily connect the closed loop multiconductor cable tester to automatically comprehensively test the cable because the plugs of opposite ends of the multiconductor cable are normally readily available for connection to the cable tester. The closed loop tester is able to test and measure test signals on each conductor in the multiconductor cable separately while monitoring all other conductors for miss-wires and other problem conditions.
After installation of the cable, the closed-loop multiconductor cable tester requires the use of an extender cable that must be temporarily installed between the closed-loop cable tester and the far end of the cable under test. Such temporary extender cables tend to be heavy. Storage, maintenance, relocation, set up, and the like, of these extender cables for testing purposes tends to be cumbersome, time consuming, and costly. Such cable may comprise twenty-five foot lengths with generic 100-pin connectors on each end. The extender cables are prone to damage when they are temporarily installed, removed, and reinstalled as a system installation progresses. The extender cables are usually laid out in general passageways where they are subject to abuse from foot traffic and other construction activities. The extender multiconductor cables inherently have a rather high susceptibility to damage due to the large number of conductors and connections therein as compared to, for instance, single conductor cable. The extender cables therefore frequently become a subject of test and repair, making tracing of the cause of problems more difficult. Damaged extender cables can significantly lengthen the system checkout process due to the introduction of additional errors during testing.
While the automated closed loop multiconductor cable tester has been preferred in the past, due to the difficulties of closed loop testing of installed multiconductor cables, an automated open loop multiconductor cable tester has also been developed. The open loop tester utilizes a shorting plug at the far end of the cable under test. The shorting plug connects all pins together. The open loop tester uses one pin (usually pin 1) as a return path. Then logic level signals are applied in sequence to each remaining pin in the connector as determined by a pre-stored wiring list. The open loop multiconductor cable tester senses if there is continuity in each individual conductor, records the results, and then sequences to the next pin. However, the open loop multiconductor cable tester does not detect all problems. For instance, if there is a miswiring problem, where the continuity of the incorrectly connected wires is otherwise good, the open loop multiconductor cable tester will not sense the error.
Various inventors have attempted to solve related problems as evidenced by the following patents, without providing the solutions taught hereinafter.
U.S. Pat. No. 3,986,106 issued Oct. 12, 1976, to Shuck et al, discloses a portable cable test set that includes a master unit connected to one end of a cable made up of multiple wire pairs and a remote unit connected to the other end. The master unit generates a series of digital pulses, a pulse being applied to a first wire of each wire pair in a predetermined sequence. The remote unit interconnects the wire pair with a resistor of predetermined resistance which differs from every other resistor and which is much greater than the resistance of the wire pair undergoing testing. A corresponding resistor of like value is included in the master unit and receives the same pulse that is applied to the wire undergoing testing. A comparator in the master unit compares the magnitude of the pulse sent over the wire pair with the magnitude of the pulse sent through the reference resistance in the master unit and a sequencer applies the next pulse to the next wire and next corresponding resistance when the preceding pulse magnitudes are equivalent. An interrupter stops the test sequence when the compared pulses are unequal in magnitude, and an indicator then identifies the wire pair having conditions activating the sequence interrupter.
U.S. Pat. No. 4,389,694, issued Jun. 21, 1983, to R. Cornwell, Jr., discloses a monitoring system for insuring the continuity and integrity of a power distribution system comprising a plurality of trailing cables, each trailing cable connected at a central station to a common power source and transmitting a power energizing signal to a load disposed at a remote location. In particular, the monitoring system comprises a transmitter and receiver for each trailing cable of the power distribution system whereby a monitoring signal is transmitted from the central station to the remote location and returned for detection by the receiver. If there is a fault condition within the trailing cable, the receiver provides a signal indicative thereof to be applied to a circuit breaker or coupling switch actuating the coupling switch to its open position thereby disconnecting the power from the trailing cable and its load. When a monitoring signal is successively transmitted and detected, the receiver provides a manifestation indicating the integrity and continuity of its trailing cable and actuates its coupling switch to its closed position, thus applying an energizing signal via its conductor to the load. The transmitter dedicated to each trailing cable includes means responsive to the frequency or frequencies of the previously generated monitoring signals, even from other transmitters, for generating a monitoring signal of substantially the same frequency whereby the monitoring signals as applied via the common AC power bus will be of substantially the same frequency. As a result, the monitoring system of this invention tends to eliminate the production of difference or beat signals and the resultant false indications of a fault condition within one or more of the trailing cables.
U.S. Pat. No. 5,027,074, issued Jun. 25, 1991, to E. C. Haferstat, discloses a cable tester for testing the individual conductors of a multiconductor cable. The cable tester includes a transmitter for connection to one end of the cable and a receiver for connection to the opposite end of the cable. The receiver includes a microprocessor having an EPROM memory. The receiver also includes an LCD display and a keypad for data input. In use the transmitter sequentially generates voltage pulses through each conductor of the cable and to the receiver. The receiver monitors these pulses at the opposite end of the cable and feeds this data into the microprocessor for processing and display on the LCD display. The cable tester quickly detects shots, opens, or crossed conductors within the cable and provides results of the testing on the LCD display.
U.S. Pat. No. 5,436,554, issued Jul. 25, 1995, to H. J. Decker, Jr., discloses a device for determining interconnections between terminal positions at opposite ends of cable includes a test circuit, connectors for connecting the test circuit to the terminal positions of the cable and a connector for interfacing the test circuit with a computer. The test circuit sequentially selects each of the terminal positions of the cable as a test point and includes a demultiplexing/multiplexing device for applying a test voltage to the selected terminal position, a resistor for maintaining a load resistance effective to provide a second logic signal at each terminal position other than the terminal position as the test point to which the test voltage is applied and to maintain a first logic signal at each terminal position to which the test voltage is not applied, a memory device for storing the logic signal present at each terminal position during application of the test voltage to the selected test point terminal position, and the demultiplexing and multiplexing device for determining, subsequent to removal of the test voltage from the test point, the logic signals stored by the memory device for each terminal position. A stored first logic signal is indicative of a terminal position not having a common connection with the test point and a stored second logic signal is indicative of a terminal position having a common connection with the test point. A method for determining interconnections between terminal positions at opposite ends of a cable includes operating the above-described device.
U.S. Pat. No. 5,565,783, issued Oct. 15, 1996, to Lau et al., discloses a method and a fault sensor device which can detect and distinguish abnormal current and voltage events on an alternating current overhead and underground transmission line or distribution line. The fault sensor device is contained in an elongated molded plastic housing, The fault sensor device includes a current sensor and a voltage sensor connected in proximity to the transmission or distribution line for monitoring current and voltage analog signals; an analog-to-digital converter connected to the current and voltage sensors for sampling the current and voltage analog signals and producing: corresponding digital signals; a processor responsive to the digital signals for detecting an abnormal condition and distinguishing whether any of a plurality of types of faults has occurred; and a transmitter for transmitting the fault information from the processor to a remote location.
U.S. Pat. No. 6,236,952 B1, issued May 22, 2001, to Jun et al., discloses a system wherein production information for ASIC (Application Specific Integrated Circuit) devices is stored in a database of a remote host system, and data necessary for a test program which controls testers for testing the IC devices is automatically created and transmitted to a tester host. This automatic system collects the data necessary for the test condition from the remote host database; creates the test condition by comparing the collected data with a predetermined handling condition; transmits the test condition to a tester host which controls a plurality of testers using corresponding test programs; and loads the test condition into the corresponding test program. This system avoids human errors which often result when test engineers write test conditions manually, and also allows quick response to a situation when new specific IC devices are required by a customer.
The above patents do not disclose a system and method operable for effectively providing the benefits of closed loop testing of multiconductor cable wherein the ends thereof are not readily available for connection to a closed loop tester without requiring a multiconductor extender cable. Those skilled in the art will appreciate the present invention which addresses the above and other problems.
Accordingly, it is an objective of the present invention to provide an improved system and method for testing multiconductor cables.
Another objective is to provide a system and method as aforesaid which may be utilized to avoid the need for multiconductor extender cables.
A further objective is to provide a system and method as aforesaid whereby the test results of the condition of the multiconductor cable are equivalent to those obtained by closed loop testing of the multiconductor cable when using multiconductor extender cables.
These and other objectives, features, and advantages of the present invention will become apparent from the drawings, the descriptions given herein, and the appended claims. However, it will be understood that the above listed objectives and advantages of the invention are intended only as an aid in understanding aspects of the invention, and are not intended to limit the invention in any way, and do not form a comprehensive list of objectives, features, and advantages.
Accordingly, the present invention provides a tester for testing multiconductor cable wherein the multiconductor cable may be comprised of a plurality of separate conductors. The tester may comprise one or more elements such as, for instance, a first cable tester unit connectable to a first end of the multiconductor cable. The first cable tester unit is preferably operable for producing one or more test signals individually on each of the plurality of separate conductors. A second cable tester unit is connectable to the second end of the multiconductor cable, which may be several hundred feet away. The second cable tester unit is operable for individually monitoring each of the plurality of separate conductors to detect the one or more test signals produced by the first cable tester unit. In preferred embodiment, a first wireless transceiver is provided for the first cable tester that is operable for wirelessly transmitting control signals for testing of the multiconductor cable. A second wireless transceiver is provided for the second cable tester operable for wirelessly transmitting test result data for the plurality of separate conductors to the first wireless transceiver. A display may be provided for displaying test results received by the first wireless transceiver from the second wireless transceiver which shows the condition of the multiconductor cable. In a preferred embodiment, individual AC power supply connections separately power the first and second cable tester units. The units may comprise a hardwired serial connection between the first cable tester unit and the second cable tester unit to provide an alternatively useable data link between the first cable tester unit and the second cable tester unit. In another embodiment, the hardwired serial connection may be provided instead of the wireless transceivers. The first and second cable tester units each preferably utilize a controller, such as a microprocessor or the like, for controlling operation of the respective cable tester units. Data may be input to the cable tester units via a PC connection. Stored data may include pin out information related to the multiconductor cable or other types of cables to be tested. The first cable testing unit and the second cable testing unit comprise separate data connections for each of the plurality of separate conductors in the multiconductor cable so that each conductor can be tested separately from the rest.
In operation, a method is provided for testing multiconductor cables which may comprise one or more steps such as producing one or more test signals on the first end of each of the plurality of separate conductors of the multiconductor cable through the first connector, individually monitoring the second end of each of the plurality of separate conductors to detect the one or more test signals and produce cable test result data, and wirelessly transmitting the cable test result data for the plurality of separate conductors from a location adjacent the second end of the multiconductor. Other steps may comprise wirelessly transmitting synchronization data related to the one or more test signals from a location adjacent the first end of the multiconductor cable. The cable test result data is preferably automatically analyzed and information related to the condition of the multiconductor cable is displayed.